Since CD (Compact Disc) appeared, it has rapidly replaced the traditional phonograph disc and audiotape. Succeeding to CD, VCD (Video Compact Disc) also appeared, and VCD has also replaced the traditional videotape. Currently, CD-ROM (Compact Disc Random only Memory) and DVD (Digital Video Compact Disc) are also very popular. The abovementioned optical discs all have smooth readable surfaces. When the user cleans or swabs the readable surface, the readable surface is apt to be scratched. Besides, when the user holds, uses or places an optical disc, its readable surface is also likely to be damaged. When laser light illuminates the scratched readable surface, abnormal refraction of laser light will occur, and thus, the data cannot be read correctly. The scratched optical discs may be the music discs or the movie discs, which have been out of print, or may store very important data. If those optical discs cannot be repaired, the loss is hard to compensate.
To solve the abovementioned problem, U.S. Pat. No. 5,423,103 and No.5964650 propose related technologies to repair optical discs. In both conventional technologies, an elastic grinding wheel, which is disposed in the direction vertical to the optical disc, is pressed with force onto the readable surface of the optical disc. Thus, the elastic grinding wheel will be deformed to contact the readable surface, and the readable surface is ground thereby. The grinding wheel has to span the optical; thus, the diameter of the grinding wheel has to be greater than that of the optical disc. Further, the grinding wheel has to be vertical to the optical. Therefore, the volume of the entire grinding device is too large to be carried about or stored up. Besides, the price of those grinding devices is very high. Thus, they are not suitable for common users.